Proposition 3.1 ([1]})  
Let \(X\)  be a TVS, \(\mathfrak {F}\)  be a Cauchy filter \(\mathfrak {F}\)  on \(X\)  and \(z \in X\)  be a cluster point of \(\mathfrak {F}\) , then \(z = \lim \mathfrak {F}\) .

